MULTI-COMPONENT MICRO-ALLOYED AIR COOLING BAINITIC STEELS

Medium carbon and medium-high carbon air cooling micro-alloyed bainitic steels of Mn-Si-B system have been studied. The main structure is bainite or bainite/martensite after forging and air cooling, and there are carbides and a small amount of retained austenite. The structure is fine and uniform, and the addition of micro-amount elements can further refine the austenite grain and the bainitic structure.By modified treatments of mono, binary and ternary micro-alloying, the structures of various grades can be obtained, and their hardness, toughness and wear resistance increase successively. The structure of the air cooling bainitic steels with medium high carbon treated by ternary micro-alloyed after forging and tempering or nomalizing and tempering is much finer, the properties are much superior.